We know that any such spray guns, whether they are automatic or manual, comprise a spray head, which channels the product to be sprayed and the pressurized propellant gas, which is usually compressed air. Such a spray head is made up by a set of parts involved in spraying the product and which are mainly:                a product spray nozzle        a gas blow cap, and        a gas distributor ring, generally referred to as the deflective ring, which supplies propellant gas to the cap and also distributes it in order to obtain a round jet and a flat jet for the sprayed product.        
In the case of the existing spray guns, the nozzle is generally fixed to the body of the spray gun, which makes it rather difficult to dismount. Yet, the nozzle is a part which by its very nature needs to be cleaned or replaced rather frequently. Furthermore, in case of the existing spray guns, the course of the spray product cannot be smooth due to the nozzle being fixed to the body and this makes it even more difficult to clean.
As a solution to this drawback, patent FR-2 788 231 describes a spray head where the nozzle can be easily dismounted, while ensuring a smooth course for the spray product through the nozzle. The spray head comprises:                a body comprising a tube to supply the spray product and an annular flat face around the free annular end of the supply tube        a tubular spray nozzle, to which the spray product is supplied by the supply tube and fitted with a spray neck at one end and an annular flat face at the other end        a seal that is suitable to be placed between the annular flat face of the nozzle and the free annular end of the supply tube        a gas blow cap        a gas distributor ring, assembled in such a way that it can be detached from the gas blow cap and supplied by pressurized gas from at least one tube envisaged in the body and which allows the cap to be supplied homogenously with gas and, possibly, to distribute the gas in such a way to vary the jet of the product at the exit of the spray neck.        a way of screwing the gas distributor ring on the body that simultaneously allows:                    the nozzle of the gas distributor ring and the body to be joined, and            to press the seal between the annular flat face of the nozzle and the free annular end of the supply tube, and                        a swivel retaining ring in order to assemble the gas blow cap and gas distributor ring in such a way that they can be detached. The gas distributor ring is threaded around its external periphery.        
Therefore, in the spray head as described in this FR-2 788 231 document, the nozzle is held by pressure between the distribution ring and the body of the spray head and may be easily assembled and disassembled by tightening and loosening the parts. Furthermore, the course of the product between the spray product tube, the seal and the nozzle is not at all bumpy and can be smooth.